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Test Id : SFEC

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Iron and Total Iron-Binding Capacity, Serum

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Overview

Test Catalog

Useful For
Suggests clinical disorders or settings where the test may be helpful

Screening for chronic iron overload diseases, particularly hereditary hemochromatosis

 

Screening for iron deficiency as the cause of anemia

 

Monitoring treatment for iron deficiency anemia

 

This test should not be used as the primary test for iron deficiency.

Profile Information
A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.

Test Id Reporting Name Available Separately Always Performed
IRON Iron No Yes
TIBC Total Iron Binding Capacity No Yes
SAT Percent Saturation No Yes

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For more information see Hereditary Hemochromatosis Algorithm.

Method Name
A short description of the method used to perform the test

IRON: Colorimetric Assay

TIBC: Turbidity/Calculation

SAT: Calculation

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Iron and Total Fe Binding Cap, S

Aliases
Lists additional common names for a test, as an aid in searching

Iron (Fe)

Iron (Serum Iron and TIBC) Routine

Iron Binding Capacity (Routine)

Latent Iron Binding Capacity

Total Iron-Binding Capacity (TIBC)

Transferrin Saturation, Serum

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For more information see Hereditary Hemochromatosis Algorithm.

Specimen Type
Describes the specimen type validated for testing

Serum

Ordering Guidance

The recommended primary test for assessment of iron deficiency is serum ferritin. Order FERR1 / Ferritin, Serum.

Additional Testing Requirements

Although measurement of serum iron, total iron-binding capacity, and percent saturation should not be used as primary testing for iron deficiency, they may be helpful when used in conjunction with ferritin and soluble transferrin receptor, especially in patients with inflammation. Order both FERR1 / Ferritin, Serum; and STFR / Soluble Transferrin Receptor (sTfR), Serum with this test.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Patient Preparation:

1. Fasting (12 hours)

2. For 24 hours before collection, patient should not take iron-containing supplements.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Draw blood before noon (preferred).

2. Within 2 hours of collection, serum gel tubes should be centrifuged.

3. Within 2 hours of collection, red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

0.5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
Frozen 180 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Screening for chronic iron overload diseases, particularly hereditary hemochromatosis

 

Screening for iron deficiency as the cause of anemia

 

Monitoring treatment for iron deficiency anemia

 

This test should not be used as the primary test for iron deficiency.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For more information see Hereditary Hemochromatosis Algorithm.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Transferrin is the plasma iron transport protein that binds iron strongly to keep iron nonreactive in circulation and deliver it to cells with transferrin receptors. The rate of transferrin synthesis in the liver can be altered according to the body’s iron requirements and iron reserves. The circulating concentration increases in response to iron deficiency and decreases in response to iron overload. Transferrin is generally only 25% to 30% saturated with iron. Total iron-binding capacity (TIBC) is estimated from the transferrin concentration using the molecular weight of transferrin, accounting for each transferrin molecule that can bind 2 atoms of iron.

 

Iron deficiency, iron overload, and anemia of chronic disease are the most prevalent disorders of iron metabolism. Serum iron, TIBC, and percent saturation are widely used for the diagnosis of iron deficiency and iron overload disorders, such as hemochromatosis. Iron concentration and percent saturation decrease with iron deficiency and increase when iron is in excess. However, serum ferritin is a much more sensitive and reliable test for demonstration of iron deficiency.

 

Anemia of chronic disease is often observed in patients with autoimmune diseases, chronic kidney diseases, inflammatory bowel disease, and chronic heart failure. It is diagnosed when serum iron concentrations are low despite normal serum ferritin concentrations indicating adequate iron stores. However, in the presence of inflammation, ferritin can mask iron deficiency; therefore, measuring soluble transferrin receptors is suggested.

 

The biologic variation of iron and, therefore, iron saturation is notable in normal healthy persons and in various clinical disorders owing to both diurnal variation and post-prandial effects. The intraindividual day-to-day variation of iron and iron saturation is approximately 25% to 30%.(1) Recommendations for blood sampling for iron and iron saturation measurements are contradictory, however; minimizing influence of these effects can be accomplished by collecting during the morning after an overnight fast.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

IRON

Males: 50-150 mcg/dL

Females: 35-145 mcg/dL

 

TOTAL IRON-BINDING CAPACITY

250-400 mcg/dL

 

PERCENT SATURATION

14-50%

Interpretation
Provides information to assist in interpretation of the test results

Serum iron concentration is elevated in iron overload conditions including hemochromatosis.(1)

 

Serum iron concentration is decreased in iron deficiency, iron deficiency anemia, and anemia of chronic disease.(1)

 

Total iron-binding capacity values are elevated in anemia of chronic disease and iron overload conditions.(1)

 

Total iron-binding capacity values are decreased in iron deficiency, iron deficiency anemia, and iron-refractory iron deficiency anemia.(1)

 

Percent saturation often exceeds 45% in hereditary hemochromatosis and 90% in advanced iron overload states.(2)

 

Percent saturation less than 16% is generally used to screen for iron deficiency, but a threshold of 20% is used in the presence of inflammation.(3)

 

For more information about hereditary hemochromatosis testing, see Hereditary Hemochromatosis Algorithm.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Serum iron, total iron-binding capacity, and percent saturation are widely used for the diagnosis of iron deficiency. However, serum ferritin is a much more sensitive and reliable test for demonstration of iron deficiency.

 

Measurement of serum iron, total iron-binding capacity, and percent saturation should not be used as the primary test for iron deficiency. It may be helpful in conjunction with ferritin and soluble transferrin receptor, especially in patients with inflammation.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Swinkels DW. Iron metabolism. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:chap 40

2. Kowdley KV, Brown KE, Ahn J, Sundaram V. ACG Clinical Guideline: Hereditary Hemochromatosis [published correction appears in Am J Gastroenterol. 2019 Dec;114(12):1927. doi:10.14309/ajg.0000000000000469]. Am J Gastroenterol. 2019;114(8):1202-1218. doi:10.14309/ajg.0000000000000315

3. Lopez A, Cacoub P, Macdougall IC, Peyrin-Biroulet L. Iron deficiency anaemia. Lancet. 2016;387(10021):907-916. doi:10.1016/S0140-6736(15)60865-0

Method Description
Describes how the test is performed and provides a method-specific reference

Iron:

Under acidic conditions, iron is liberated from transferrin. Lipemic samples are clarified by the detergent. Ascorbate reduces the released Fe(3+) ions to Fe(2+) ions which then react with FerroZine to form a colored complex. The color intensity is directly proportional to the iron concentration and can be measured photometrically.(Package insert: IRON2. Roche Diagnostics; V9, 09/2019)

 

Transferrin:

Human transferrin forms a precipitate with a specific antiserum, which is determined turbidimetrically.(Package insert:TRSF2 reagent. Roche Diagnostics; v10.0, 04/2022)

 

Calculations:

Total iron-binding capacity (TIBC) = Transferrin x 1.18

Percent saturation = (Iron/TIBC) x 100

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Sunday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 to 2 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

83540-Iron

83550-Iron-binding capacity

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
SFEC Iron and Total Fe Binding Cap, S 50190-8
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
SAT Percent Saturation 2502-3
IRON Iron 2498-4
TIBC Total Iron Binding Capacity 2500-7

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports

Test Update Resources

Change Type Effective Date
New Test 2024-10-03